U.S. warplanes are pounding Afghanistan in the second week of relentless campaign to flush out suspected terrorist Osama bin Laden and members of his al-Qaida group hiding in the country. The group is threatening to retaliate against the United States and Britain.

An Afghan news service reports U.S. bombs struck military targets and the airport in the southern Afghan city of Kandahar, causing a fire. The city is the stronghold of the ruling Taleban movement, which is sheltering terror suspect Osama bin Laden.

The Pakistan-based Afghan Islamic Press says American jets have also carried out five raids on Herat airport in western Afghanistan. It says some bombs have hit nearby residential areas, but there are no immediate reports of casualties. Raids are also reported in Kabul and other cities.

Some reports say anti-aircraft opened fire when an unidentified plane flew over the Afghan capital, Kabul. Witnesses are quoted as saying the fire from the ground was week and sporadic, indicating the city's anti-aircraft defenses may have suffered serious damage in U.S. led air strikes.

Earlier, a spokesman for al-Qaida warned American and British Muslims not to ride in planes or live in high-rise buildings. The "storm of hijacked planes," as he described it, will not stop until the attacks against Afghanistan end.

The United States has dismissed the statement as propaganda from the group, which it accuses of carrying out last month's terrorist attacks on U.S. cities.

Taleban leaders say the U.S.-led air raids have killed more than 300 civilians, though there has been no independent confirmation. Washington maintains it is not targeting civilians, but officials acknowledged on Saturday that a U.S. bomb mistakenly hit a residential site in the Afghan capital.

Meanwhile, a group of Western journalists, closely guarded by Taleban authorities, have entered Taleban-controlled Afghanistan. They are the first foreign journalists allowed to do so since the attacks began a week ago.